Hiroshi hirata

ABSTRACT

1. A DEVICE FOR CHECKING VOLTAGE OF A POWER SOURCE BATTERY IN A MOTION PICTURE CAMERA (DRIVE BY A) HAVING AN ELECTRIC DRIVING MOTOR FOR DRIVING FILM IN THE CAMERA AT VARIOUS SPEEDS, AND (CAPABLE OF) MEANS TO SELECT THE SPEED OF OPERATION OF SAID MOTOR TO ENABLE SHOOTING WITH VARIOUS FRAME SPEEDS OVER A WIDE RANGE SAID DEVICE COMPRISING, A GALVANOMETER FOR INDICATING WHETHER ELECTRIC CURRENT FLOWING THROUGH IT IS GREATER (OF) OR LESS THAN A PREDETERMINED LEVEL; (AN ELECTRIC DRIVING MOTOR FOR DRIVING THE FILM IN THE CAMERA AT VARYING SPEED; MEANS TO SELECT THE SPEED OF OPERATION OF SAID MOTOR;) A RESISTOR ASSEMBLY CONNECTED IN SERIES WITH SAID GALVANOMETER, AND MEANS FOR VARYING THE RESISTANCE VALUE OF SAID RESISTOR ASSEMBLY IN RESPONSE TO THE SELECTION OF A FRAME SPEED AND CORRESPONDING GENERALLY WITH THE INTERNAL IMPEDANCE OF SAID DRIVING MOTOR WHILE RUNNING AT THE SELECTED FRAME SPEED; SAID GALVANOMETER AND RESISTOR ASSEMBLY FORMING A CIRCUIT TO BE CONNECTED TO THE POWER SOURCE BATTERY, SAID CIRCUIT BEING CONNECTED IN PARALLEL WITH THE DRIVING MOTOR.

P" 7 HIROSHI HIRATA Re. 28,393

DEVICE FOR CHECKING DRIVING BATTERY VOLTAGE IN A MQTIOH-PICTURE CAMERAWITH A WIDE RANGE OF FRAIE SPEED Original Filed March 4, 1969 2Sheets-Sheet 1 FIG. I

3/ f; F ,l I] J i 7 HIROSHI HIRATA Re. 28,393

DEVICE FOR CHECKING DRIVING BATTERY VOLTAGE IN A MOTION-PICTURE CAMERAWITH A WIDE RANGE OF FRAHE SPEED 2 Sheets-Sheet I Original Filed larch4, 1969 FIG. 3

United States Patent Re. 28,393 Reissued Apr. 15, 1975 28,393 DEVICE FORCHECKING DRIVING BATTERY VOLTAGE IN A MOTION-PICTURE CAMERA WITH A WIDERANGE OF FRAME SPEED Hiroshi Hirata, Sakai, Japan, assignor to MinoltaCamera Kabushiki Kaisha, Osaka, Japan Original No. 3,583,800, dated June8, 1971, Ser. No. 804,069, Mar. 4, 1969. Application for reissue Nov. 2,1971, Ser. No. 194,958

Claims priority, application Japan, Mar. 8, 1968, 43/ 18,094; Mar. 27,1968, LS/24,258 Int. Cl. G03b 17/18 US. Cl. 352170 5 Claims Matterenclosed in heavy brackets II] appears in the original patent hut formsno part of this reissue specification; matter printed in italicsindicates the additions made by reissue.

ABSTRACT OF THE DISCLOSURE A device for checking the battery voltage fora motion picture camera which is capable of shooting with any of aplurality of frame speeds. The device checks whether the voltage of thepower source battery is sufficient for the shooting at a certain framespeed, and the value of voltage required for shooting at that speed isset. An electric circuit for the checking device is adjusted incooperation with the selection of the frame speed.

This invention relates to a device for checking the driving batteryvoltage in a motion-picture camera with a wide range of frame speed(hereinafter called merely frames) and more particularly to a device forchecking whether or not the voltage of the driving batteries is above acertain level for guaranteeing camera operation over a wide range ofshooting speed, such as 64, 48, 32, 24, 18, 12 and 8 frames per second.Response to the change in the number of frames is so small that thedriving current can be considered to be constant in a certain range offrames.

Generally, it is known that a battery has such characteristics that whenthe battery is connected with a load to supply power thereto, thereoccurs a voltage drop in the battery due to the internal resistance, andthat the voltage applied across the load is correspondingly affected.Therefore, when we check voltage of a power source battery for driving amotor of a motion picture camera, it is important to consider theinternal voltage drop of the battery. Accordingly, in present checkingdevices, the resistance value corresponding to the impedance in thedriving motor is set in a checker circuit, and the voltage of thebattery is checked by observing whether or not the terminal voltageoccurring across the resistor by the current flowing therethrough isgreater than a predetermined level or below.

Generally, it is also known that the internal impedance of the motorincreases in proportion to its rate of speed. Therefore, most knownbattery checkers employed in motion picture cameras have, in theirchecking circuit, a resistor having resistance value corresponding tothe internal impedance of the motor which is adjusted so as to providein the camera a shooting of maximum speed of film or maximum speed orfrequency of frame, for instance, 24 frequencies of frames per second ina camera capable of shooting by frame speeds or frequencies of 24, 18and 12, whereby the voltage value across the resistor is checked toobserve whether the battery voltage is higher than the limit voltagenecessary for shooting at maximum frame speed or frequency. In otherwords, known battery checkers check the voltage for the maximum framespeed and use the checked value for checking the voltage of the batteryover the entire range of frame speeds.

However, so that the impedance of the driving motor is in proportion tothe speed, the internal impedance of the driving motor at low framespeeds, except for the maximum frame frequency, is lower than that withthe latter, and thus the guaranteed voltage as determined by the knownbattery checkers inaccurately check at the lower frame speed.

This voltage inaccuracy is not large it the range of frame speeds iscomparatively narrow, for instance, 24, 18 and 12 frames per second.However, if the range of frame speeds becomes very wide, such as a rangecovering 64, 48, 32, 24, 18 and 12 frames per second, the voltageinaccuracy becomes large, and the known voltage checking deviceguarantees a driving voltage for the maximum number of frames (eg 64),which is not usually used, and provides a too large an allowance ortolerance for the minimum number of frames per second. Furthermore, thedriving voltage high enough for most frequently used number of framespeeds (e.g., 24, 18 and 12 frames) in a very wide range may bedetermined by the known voltage checking device to be insufficient, andthe utility of the driving batteries is unduly and extensivelycurtailed. Thus, the known voltage checking device has noticeabledrawbacks.

Accordingly, there is a need for overcoming the aforesaid difticulty ofthe known battery checker in a motionpicture camera having a wide rangeof frame speeds, so as to make full use of the driving batteries.

There is no motion-picture camera available at present which meets theaforesaid need by incorporating a suitable battery checker. It has beenproposed to add a tachometer to a motion-picture camera in order tofacilitate checking whether or not a given voltage is sufiicient foreach frame speed chosen. According to the proposed scheme, the drivingspeed of the motion-picture camera is at first measured, and thechecking of an effective driving voltage is carried out indirectly byusing the driving speed thus measured, so as to improve the utility ofthe driving batteries. As a result, unless a camera driving motor isactuated, it is impossible to check whether or not the driving batterieshave sufficient voltage for a selected frame speed. Thus, it becomesnecessary to check the available range of frame speeds prior to loadinga film in the camera, by operating the camera without film. If suchchecking is made before loading the film, the driving battery voltageshould be checked while shooting to find whether a particular framespeed can be run with a given driving voltage.

Therefore, an object of the present invention is to provide an improvedbattery checking means for a motion picture camera capable of shootingat various frame speeds extending over a wide range, which eliminatesthe necessity of the tachometer as referred to above and includes in thechecker circuit a resistor, the resistance value of which is adjusted incooperation with the selection of frame speed so as to correspond withthe internal impedance of the driving motor speed in accordance with theselected frame speed, whereby the limit voltage for each frame speed ischecked by a single or common calibration with which the current flowingthrough the checker circuit is gauged, and thus the utility of thebattery is improved.

Another object of this invention is to provide a battery checking devicefor a camera as set forth above, wherein the range of frame speeds isdivided into a plurality of groups, and resistance value of theresistors is selected in cooperation with the frame speed selected so asto correspond with the internal impedance of the rotating motor toattain the maximum frame speed which is included in each group of framespeeds, whereby the limit voltage for each frame speed is checked atevery group.

A further object of this invention is to provide a battery checkingdevice for the camera set forth above, wherein the battery checkercircuit has a variable resistance arranged therein, the resistance valueof which is adjusted in cooperation with the selection of the framespeed, whereby suitable resistance values corresponding to the internalimpedance of the driving motor is set in the checker circuit onselection of respective frame speeds.

A still further object of this invention is to provide a battery checkercircuit for a camera to which a particular power source is applied whena shooting at a high frame speed is carried out, wherein a combinationof resistance is changed in cooperation with the application of theparticular power source, whereby limit voltages for shooting by high andlow frame speeds are checked respectively.

Other objects and a fuller understanding of the present invention may behad by referring to the following description, taken in conjunction withthe accompanying drawings, in which;

FIG. 1 is a circuit diagram of an embodiment of the present invention,in which a given range of frame speeds is divided into two groups foreffecting a checking operation relative to each group;

FIG. 2 is a circuit diagram of another embodiment of the invention, inwhich checking is effected for each frame speed; and

FIG. 3 is a circuit diagram of a further embodiment of the presentinvention, which includes a portion for a high group of frame speeds andanother portion for a low group of frame speeds, so that separatedriving batteries can be used for effecting high speed shooting.

In the circuit diagram of FIG. 1, a wide range of frame speeds,including 64, 48, 32, 24, 18, 12, and 8 frames per second, is dividedinto two groups; namely a first group covering 64 frames to 32 framesper second, and a second group covering 24 frames to 8 frames persecond. Batteries 1, a driving motor 2, a frame speed selector switch 3,and a release switch 4 constitute a driving circuit. A battery voltagechecking circuit consists of a battery checker or galvanometer 5 of aconventional design, a resistor assembly 6 for checking the limitvoltage of the driving batteries, and a checker switch 7, all connectedin series, and the battery voltage checking circuit is connected acrossthe batteries 1 in parallel therewith. The resistor assembly 6 includesa resistor element 8 having resistance values corresponding to theinternal impedance of the driving motor 2 rotating to achieve aphotographing of 24 frames per second, a resistor element 9 togetherwith which the element 8 produces a combined resistance valuecorresponding to the internal impedance of the driving motor 2 rotatedto attain a photographing at 64 frames per second, and a switch 10electrically connected across the resistor element 9 and mechanicallyinterconnected with the frame selector switch 3 so as to be gangoperated therewith, as illustrated in the figure. The resistor element 8is connected in series with the resistor element 9, and the switch 10 isconnected in parallel with the resistor element 9. The switch 10incorporated in the resistor assembly 6 has a stationary contact 11connected to the junction point between the resistor elements 8 and 9and a selector arm connected to the junction point between the resistorelement 9 and the checker switch 7. For high speed shooting (64, 48 and32) which are not usually used, the selector arm is at such angularpositions that a circuit between the selector arm and the contact isopen, while for low frame speeds (24, 18, 12 and 8 frames), the selectorarm is kept in contact with the contact 11.

When a shooting speed of 64 frames per second is selected, as shown inFIG. 1, the battery voltage checking circuit is completed upon closingof the checker switch 7, and the galvanometer 5 indicates whether or notthe voltage of the battleries 1 is above a limit voltage guaranteeingthe 64 frame shooting speed, by using both the resistor element 8 andthe resistor element 9 with the limit voltage changeover switch 10 beingopen under such conditions. It is apparent that when the frame speedselector 3 is at the 48 frame position or at the 32 frame position, thegalvanometer or battery checker 5 gives the same indication as theaforesaid indication for the shooting speed of 64 frames per second.

If the galvanometer 5 indicates that the voltage of the batteries 1 isbelow the limit voltage guaranteering the high speed shooting with theframe selector 3 in the range 64 to 32 frames per second, or ifinsufiicient voltage of the batteries 1 for such high speed shooting isindicated, the frame selector 3 may be turned to the 24-position (or tothe l8, 12 or 8 frame position). Then, the selector arm of the switch 10is gang operated with the frame speed selector switch 3 and is broughtinto contact with the cooperating stationary contact 11, so that theresistor element 9 of the resistor assembly 6 is short-circuited by thechangeover switch 10. The characteristic of the battery voltage checkingcircuit is such that, with the resistor element 9 shunted through theswitch 10, the galvanometer or battery checker 5 indicates whether ornot the batteries 1 have voltage higher than another limit voltageguaranteeing a shooting speed of 24 frames per second. Such indicationof the voltage of the batteries 1 by the battery checker 5 is based onthe magnitude of the current through the galvanometer 5. As pointed outin the foregoing, the magnitude of the driving current through thedriving circuit (not shown) of a motion-picture camera (not shown) issubstantially constant for a comparatively narrow range of shootingspeeds, and the limit voltage guaranteeing the shooting at a given speedis reduced as the shooting speed becomes slower. Accordingly, if thegalvanometer 5 indicates that the batteries 1 have a voltage lower thanthe limit voltage for 64 frames but higher than for 24 frames, thebatteries 1 are still usable for the low speed group covering 24, 18, 12and 8 frames, and hence the batteries need not be replaced as long asthe shooting is made in the low speed group of frames.

In the aforesaid first embodiment of the present invention, a wide rangeof different shooting speeds of a motionpicture camera are divided intotwo groups, and the voltage of the driving batteries is checked for thetwo groups of shooting speeds, respectively. FIG. 2 illustrates anotherembodiment of the invention (parts similar to those of FIG. 1 aredesignated by similar reference numerals), in which the resistorassembly 6 is substituted for by a rheostat 12 consisting of a resistorand a slider arm 13 gang operated with a frame speed selector switch 3,so that the resistance value of the rheostat 12 can be automaticallyvaried for facilitating the checking of the driving battery voltagerelative to the internal impedance of the driving motor rotated forguaranteeing each of the different shooting speeds, respectively. Withsuch rheostat 12, a battery voltage checker such as a galvanometer 5 canindicate whether or not the voltage of batteries 1 is higher than alimit voltage guaranteeing camera operation at a given speed, whichlimit speed can be set individually for each shooting speed or eachnumber of frames per second. Thus, with the circuit construction of FIG.2, the driving battery voltage can be checked relative to each of thelimit voltages present for each of the various selectable shootingspeeds, so that the utility of the driving batteries can be furtherimproved.

As can be seen from the above embodiments, by using the device forchecking the driving battery voltage according to the present invention,the voltage of the driving batteries can be checked by comparing with alimit voltage guaranteeing camera operation at a particular shootingspee d or at the highest number of frames per second in each of thedivided groups over the full range covering the highest shooting speedto the lowest shooting speed of the camera. Accordingly, if the drivingbatteries have a voltage lower than the limit voltage guaranteeing ahigh speed shooting or shooting at one of high group of speeds buthigher than another limit voltage guaranteeing a low speed shooting orshooting at one of the low group of speeds, the driving batteries can beused for the low speed shooting without replacement. Thus, the drivingbatteries can be used to their full capacity. Furthermore, with thedevice according to the present invention, an operator need not make anyseparate switching operation for changing the limit voltage when achange is made in the shooting speed, either between divided stages ofshooting speeds or among individual shooting speeds. The driving batteryvoltage can be checked simply by closing a checker switch because uponturning of a speed selector switch, a limit voltage switch is gangoperated so as to efiect continuous checking of the driving batteryvoltage relative to different limit voltages guaranteeing individualselected shooting speeds or selected groups of shooting speeds,respectively. Thus, the available shooting speed for given drivingbatteries can easily be checked. In addition with the device of thepresent invention, the driving battery voltage can be checked relativeto limit or minimum voltages without necessitating actuation of a cameradriving motor, which was necessary in known motion-picture camerasequipped with tachometers.

FIG. 3 illustrates a further embodiment of the device according to thepresent invention. A camera body 14 has a receptacle 17 adapted toreceive a plug 16a of a battery assembly 16 for actuating a drivingmotor 15 at a speed in a high speed shooting range covering 64, 48 and32 frames per second. When the plug 16a of the battery assembly 16 isseparated from the receptacle 17, as shown in the figure, themotion-picture camera (not shown) is driven by batteries 18 used for lowspeed motion. In other words, the batteries 18 are used for driving thecamera in a low group of shooting speeds (e.g., 24, 18, 12 and 8 framesper second). Under the illustrated circuit conditions, a contact 19disposed at the back of the receptacle 17 has one end kept in contactwith a stationary contact 20 connected to the batteries 18 and the otherend of the contact 19 is kept in contact with another stationary contact23 for shunting a resistor element 22 for checking the batteries 21 ofthe battery assembly 16 for the group of high shooting speeds. Thecontact 19 is connected to circuit consisting of a camera driving motor15 and a release switch 24 and to another circuit including the resistorelement 22 for checking the batteries 21, another resistor element 25for checking both batteries 18 and 21, a battery checker 26 such as agalvanometer and a checker switch 27.

The battery assembly 16 for the high shooting speeds comprises the plug16a and the batteries 21. The plug 16a includes a conductive stem 16b, aconductive cylinder 16c, an insulating outer cylinder 16d, andinsulating members 16e and 16f for insulating the stern 16b from thecylinder 16c. When the plug 16a is inserted in the receptacle 17, thestem 16b engages a contracted portion 28 of the contact 19, so as tomove the opposing end of the contact 19 away from each other. Thus, thecircuit between the contact 19 and the stationary contact 20 and theother circuit between the contact 19 and the other stationary contact 23are interrupted. The conductive cylinder 160 is grounded to the camerabody 14 through the receptacle 17, when the plug is inserted in thereceptacle. The stem 16b of the plug 16a is connected to one terminal ofthe batteries 21, while the cylinder 16c is connected to the Oppositeterminal of the batteries 21.

As can be seen from the figure, the voltage of the batteries 18 for lowframe speeds can be checked by a battery voltage checking circuittracing from one terminal of the batteries 18, through the stationarycontact 20, the contact 19, the other stationary contact 23, theresistor element 25, the galvanometer 26, and the checker switch 27, andback to the opposite terminal of the batteries 18. The voltage of thehigh speed (e.g., 64, 48 and 32 frames) driving bat teries 21 is checkedby completing another battery voltage checking circuit by inserting theplug 16a in the receptacle 17, which circuit traces from one terminal ofthe batteries 21, through stem 16b, the contact 19, resistor elements22, 25, the galvanometer 26, and the checker switch 27, and back to theother terminal of the batteries 21 which other terminal is groundedthrough the cylinder 16c and the receptacle 17 secured to the camerabody 14. Thus, for the high speed and low speed groups the batteryvoltage checking circuit can be automatically changed over between thehigh speed checking circuit and the low speed checking circuit inresponse to the insertion and removal of the battery assembly 16 intoand away from the camera body.

The operation of the embodiment of FIG. 3 will now be described. Duringcamera operation in the low speed group, the battery voltage checkingcircuit for the driving batteries 18 is completed upon closing of thechecker switch 27, so that the galvanometer 26 indicates the voltagecondition of the batteries 18. When the plug 16a of the high speedbattery assembly 16 is inserted in the receptacle 17 of the camera body14 for effecting high speed shooting, the contact 19 is separated fromboth the stationary contact 20 and the other stationary contact 23 bythe stem 16b. Then, upon closing of the checker switch 27, the otherbattery voltage checking circuit for the high speed driving batteries 21is completed, so that the galvanometer 26 indicates the voltagecondition of the batteries 21.

As described in the foregoing, according to the present invention, thevoltage checking of the driving batteries for low and high shootingspeeds is effected separately, so that the utility of the batteries isgreatly improved. Furthermore, the changeover of the battery voltagechecking circuits can be carried out very easily in an automatic fashionin response to the mounting and the separation of the battery assemblyfor high speeds to the motion-picture camera.

Although the present invention has been described with a certain degreeof particularity, it is understood that the present disclosure has beenmade only by way of example and that numerous changes in the details ofconstruction and the combination and arrangement of parts may beresorted to without departing from the spirit and the scope of theinvention as hereinafter claimed.

What I claim is:

1. A device for checking voltage of a power source battery in a motionpicture camera [drive by a] having an electric driving motor for drivingfilm in the camera at various speeds, and [capable of] means to selectthe speed of operation of said motor to enable shooting with variousframe speeds over a wide range said devise comprising,

a galvanometer for indicating whether electric current flowing throughit is greater [of] or less than a predetermined level;

[an electric driving motor for driving the film in the camera at varyingspeed; means to select the speed of operation of said motor;]

a resistor assembly connected in series with said galvanometer, andmeans for varying the resistance value of said resistor assembly inresponse to the selection of a frame speed and corresponding generallywith the internal impedance of said driving motor while running at theselected frame speed;

said galvanometer and resistor assembly forming a circuit to beconnected to the power source battery, said circuit being connected inparallel with the driving motor.

2. A device as claimed in claim 1, wherein the [range] frame speeds aredivided into a plurality of groups, and said resistor assembly [havinga] has resistance [value] values corresponding generally with theinternal impedance of the driving motor while running to provide [a] forshooting at the respectively highest frame speed in each group of theframe speeds, said resistance values being selected in response to theselection of the frame speed.

3. A device as claimed in claim 1, including a frame speed selector, theresistor assembly including a rheostat [with] including a slider armgang operated with said frame speed selector to change the effectiveresistance of the rheostat in response to the selection of the framespeed.

4. A device as claimed in claim 1, wherein said power source batterycomprises a first battery adapted for shooting at low frame speeds and asecond battery adapted to provide for shooting at high speeds andwherein the resistor assembly consists of a first resistor for checkingthe voltage of [a] said first battery [applied] adapted for [the]shooting at low frame speeds and a second resistor associated with thefirst resistor for checking the voltage of [a] said second battery,[said second battery being substituted for said first battery byinserting said second battery in the motor driving circuit for shootingat high frame speeds, and] said device further Comprising a shortcircuit across the second resistor, said short circuit being opened [onthe insertion of] when the second battery is coupled to said motor.

5. A device as claimed in claim 4, including a camera body supportingsaid motor and plug means insertable in [a] said camera body, said plugmeans operating to interrupt the electrical connection between the firstbattery and said motor and [device, and] electrically connect the secondbattery to said motor and [the device and] open said short circuit forthe second resistor.

References Cited The following references, cited by the Examiner, are ofrecord in the patented file of this patent or the original patent.

UNITED STATES PATENTS RICHARD C. QUEISSER, Primary Examiner D. E. CORR,Assistant Examiner US. Cl. X.R.

